AISI 321 Stainless Steel vs. SAE-AISI 8740 Steel
Both AISI 321 stainless steel and SAE-AISI 8740 steel are iron alloys. They have 72% of their average alloy composition in common. There are 31 material properties with values for both materials. Properties with values for just one material (2, in this case) are not shown.
For each property being compared, the top bar is AISI 321 stainless steel and the bottom bar is SAE-AISI 8740 steel.
Metric UnitsUS Customary Units
Mechanical Properties
| Brinell Hardness | 170 to 210 | |
| 170 to 200 |
| Elastic (Young's, Tensile) Modulus, GPa | 200 | |
| 190 |
| Elongation at Break, % | 34 to 50 | |
| 11 to 23 |
| Fatigue Strength, MPa | 220 to 270 | |
| 270 to 350 |
| Poisson's Ratio | 0.28 | |
| 0.29 |
| Shear Modulus, GPa | 77 | |
| 73 |
| Shear Strength, MPa | 420 to 460 | |
| 370 to 400 |
| Tensile Strength: Ultimate (UTS), MPa | 590 to 690 | |
| 580 to 670 |
| Tensile Strength: Yield (Proof), MPa | 220 to 350 | |
| 380 to 570 |
Thermal Properties
| Latent Heat of Fusion, J/g | 290 | |
| 250 |
| Maximum Temperature: Mechanical, °C | 870 | |
| 410 |
| Melting Completion (Liquidus), °C | 1430 | |
| 1460 |
| Melting Onset (Solidus), °C | 1400 | |
| 1420 |
| Specific Heat Capacity, J/kg-K | 480 | |
| 470 |
| Thermal Conductivity, W/m-K | 16 | |
| 39 |
| Thermal Expansion, µm/m-K | 17 | |
| 13 |
Electrical Properties
| Electrical Conductivity: Equal Volume, % IACS | 2.4 | |
| 7.3 |
| Electrical Conductivity: Equal Weight (Specific), % IACS | 2.7 | |
| 8.4 |
Otherwise Unclassified Properties
| Base Metal Price, % relative | 16 | |
| 2.6 |
| Density, g/cm3 | 7.8 | |
| 7.8 |
| Embodied Carbon, kg CO2/kg material | 3.2 | |
| 1.5 |
| Embodied Energy, MJ/kg | 45 | |
| 20 |
| Embodied Water, L/kg | 140 | |
| 50 |
Common Calculations
| Resilience: Ultimate (Unit Rupture Work), MJ/m3 | 190 to 230 | |
| 71 to 120 |
| Resilience: Unit (Modulus of Resilience), kJ/m3 | 130 to 310 | |
| 390 to 850 |
| Stiffness to Weight: Axial, points | 14 | |
| 13 |
| Stiffness to Weight: Bending, points | 25 | |
| 24 |
| Strength to Weight: Axial, points | 21 to 25 | |
| 20 to 24 |
| Strength to Weight: Bending, points | 20 to 22 | |
| 20 to 22 |
| Thermal Diffusivity, mm2/s | 4.1 | |
| 10 |
| Thermal Shock Resistance, points | 13 to 15 | |
| 17 to 20 |
Alloy Composition
| Carbon (C), % | 0 to 0.080 | |
| 0.38 to 0.43 |
| Chromium (Cr), % | 17 to 19 | |
| 0.4 to 0.6 |
| Iron (Fe), % | 65.3 to 74 | |
| 96.5 to 97.7 |
| Manganese (Mn), % | 0 to 2.0 | |
| 0.75 to 1.0 |
| Molybdenum (Mo), % | 0 | |
| 0.2 to 0.3 |
| Nickel (Ni), % | 9.0 to 12 | |
| 0.4 to 0.7 |
| Nitrogen (N), % | 0 to 0.1 | |
| 0 |
| Phosphorus (P), % | 0 to 0.045 | |
| 0 to 0.035 |
| Silicon (Si), % | 0 to 0.75 | |
| 0.15 to 0.35 |
| Sulfur (S), % | 0 to 0.030 | |
| 0 to 0.040 |
| Titanium (Ti), % | 0 to 0.7 | |
| 0 |